In wireless communication techniques, when a base station side (for example an Evolved Node BeNB) transmits data through multiple antennas, data transmission rate can be improved through spatial multiplexing, i.e., transmitting different data at different antenna locations using same time-frequency resources on the transmission end, and a reception end (for example a User Equipment UE) also use multiple antennas to receive the data. In the case of a single user, resources of all antennas are assigned to a same user, the user occupies exclusively, during a transmission interval, physical resources assigned by the base station side, this transmission mode is referred to as Single User Multiple-Input Multiple-Out-put (SU-MIMO); in the case of multiple users, spatial resources of different antennas are assigned to different users, one user and at least one other user share, during a transmission interval, physical resources assigned by the base station side, and the way of sharing can be SDMA or space division multiplexing, this transmission mode is referred to as Multiple User Multiple-Input Multiple-Out-put (MU-MIMO), wherein the physical resources assigned by the base station side refer to time-frequency resources.
Standards of Long-Term Evolution (LTE) define a Physical Downlink Control Channel (PDCCH) configured to carry Downlink Control Information (DCI) including uplink/downlink scheduling information and uplink power control information. Formats of DCI in LTE Release 10 include: DCI format 0, DCI format 1, DCI format 1A, DCI format 1B, DCI format 1C, DCI format 1D, DCI format 2, DCI format 2A, DCI format 2B, DCI format 2C, DCI format 3, DCI format 3A and DCI format 4. With the development of CoMP techniques, LTE Release 11 puts forward an enhanced PDCCH, namely ePDCCH, the time domain starting position and frequency domain starting position of which are quite different from those of the PDCCH.
LTE also defines Transmission Mode (TM) selected by each UE PDSCH transmission. At present, Release 10 defines 9 transmission modes including TM 1 to TM 9, wherein the DCI Format 1A, serving as a fallback for each transmission mode, is mainly used when channel measurement is not reliable.
In addition, in LTE Release 10, the MIMO transmission mode uses by default a Demodulation Reference Signal (DM-RS) as a pilot carrier for demodulation, and a UE needs to acquire the position of the pilot carrier so that channel and interference estimation can be made on the pilot carrier; at a starting of a subframe, an initialized value of a DM-RS sequence is cinit=(└ns/2┘+l)·(2NIDcell+1)·216+nSCID, wherein nSCID represents a Scrambling Identity (SCID) configured to support two different scrambling sequences, and the eNB can assign these two scrambling sequences to different users so that a same resource can be multiplexed by multiple users; NIDcell represents a cell Identity (ID) with values being integers between 0 and 503; as the development CoMP techniques, LTE Release 11 puts forward enhancement of the DM-RS, which exhibits that the initialized value of the DM-RS sequence is changed to:
Cinit=(└ns/2┘+l)·(2X+l)·216+nSCID, wherein a scrambling initialized value X is a scrambling initialized value used when the DM-RS sequence is initialized, it can take two values x(0) and x(1), x(n) takes an integer between 0 and 503, which is configured by a higher layer.
With the development of LTE-A carrier aggregation techniques, LTE R11 puts forward a new type of carrier, which is still under discussion, it can be determined that for the new carrier, a single port Cell Reference Signal (CRS) according to LTE R8/R9/R10, which has a period of 5 ms, is used to perform synchronous tracking, and in a transmission mode, demodulation is performed based on the DM-RS, and channel measurement is performed based on the CSI-RS; it is determined that DCI Format 1A and DCI format 2C can be used in scheduling of a PDSCCH, and transmission modes supported in Coordinated Multi-Point (COMP) are specified and it is specified that DCI format must be supported in the newly added carrier, thus it can be learned that the enhancement of the DM-RS is also desired to be supported in the newly added carrier.
At present, for transmission of new carriers, it is specified that the DCI Format 1A schedules a PDSCH of the UE using an approach of single DM-RS antenna port transmission, but a specific DM-RS antenna port is not specified, and multiple DM-RS antenna ports are needed for implementing PDSCH transmission diversity to ensure the reliability of transmission in the future; for reasons of interference elimination and increase of multiplexing capacity for MU-MIMO, it is desired to select dynamically transmission parameters of the PDSCH such as a DM-RS antenna port in use, and an SCID and a scrambling code initialized value X desired when a DM-RS port sequence is initialized. However, so far no new PDSCH transmission method has been proposed by related techniques so as to solve problems such as selection of DM-RS antenna ports, improvement on transmission reliability using multiple DM-RS antenna ports, interference elimination, increasing of multiplexing capacity and improvement on frequency selective gain.